What type of files does the blackberry play? Most players can play MP4 and MOV files you just need to set it to convert the way you need it for the Blackberry. You'll need to have DVD Fab with the mobile option to do these. I have DVD Fab Platinum.
My phone can play the Ipod format and I use these settings
IPod Settings for Phone Video in HTC 8525
15 - 25 FPS
175 - 200 Bitrate
32 kbs audio
These work good for my situation. I suggest you look in your phones manual. They usually tell you what type of video your unit will play and the optimal Frams Per Second, Bit Rate etc that you should use in your files conversion.
If you don't have the manual for your phone this information should be available at the MFG's website.